#26 fix.

src/main/java/io/kamax/mxisd/hash/engine/HashEngine.java

@@ -0,0 +1,66 @@
+package io.kamax.mxisd.hash.engine;
+
+import io.kamax.mxisd.config.HashingConfig;
+import io.kamax.mxisd.hash.storage.HashStorage;
+import io.kamax.mxisd.lookup.ThreePidMapping;
+import io.kamax.mxisd.lookup.provider.IThreePidProvider;
+import org.apache.commons.codec.digest.DigestUtils;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Base64;
+import java.util.List;
+
+public class HashEngine implements Engine {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(HashEngine.class);
+
+    private final List<? extends IThreePidProvider> providers;
+    private final HashStorage hashStorage;
+    private final HashingConfig config;
+    private final Base64.Encoder base64 = Base64.getUrlEncoder().withoutPadding();
+    private String pepper;
+
+    public HashEngine(List<? extends IThreePidProvider> providers, HashStorage hashStorage, HashingConfig config) {
+        this.providers = providers;
+        this.hashStorage = hashStorage;
+        this.config = config;
+    }
+
+    @Override
+    public void updateHashes() {
+        LOGGER.info("Start update hashes.");
+        synchronized (hashStorage) {
+            this.pepper = newPepper();
+            hashStorage.clear();
+            for (IThreePidProvider provider : providers) {
+                try {
+                    LOGGER.info("Populate hashes from the handler: {}", provider.getClass().getCanonicalName());
+                    for (ThreePidMapping pidMapping : provider.populateHashes()) {
+                        LOGGER.debug("Found 3PID: {}", pidMapping);
+                        hashStorage.add(pidMapping, hash(pidMapping));
+                    }
+                } catch (Exception e) {
+                    LOGGER.error("Unable to update hashes of the provider: " + provider.toString(), e);
+                }
+            }
+        }
+        LOGGER.info("Finish update hashes.");
+    }
+
+    @Override
+    public String getPepper() {
+        synchronized (hashStorage) {
+            return pepper;
+        }
+    }
+
+    protected String hash(ThreePidMapping pidMapping) {
+        return base64.encodeToString(DigestUtils.sha256(pidMapping.getValue() + " " + pidMapping.getMedium() + " " + getPepper()));
+    }
+
+    protected String newPepper() {
+        return RandomStringUtils.random(config.getPepperLength(), true, true);
+    }
+}